[Update 3:51 p.m. ET] Lt. Tim Jones of the Johnson County sheriff's department told CNN that "911 is going off the wall with people calling in with reports of sightings."

He reported multiple tornado touchdowns across the county, including in the city of Cleburne, south of Fort Worth and southwest of Dallas.

A new tornado warning was issued about 2:45 p.m. CT for Arlington, which is between Dallas and Fort Worth.

[Update 3:40 p.m. ET] DFW airport spokesman David Magana told CNN that people in the airport's passenger terminals had been herded away from windows in waiting areas.

"We have all kinds of shelters. We use all the available space we have including stairwells, store rooms and restrooms, that we can use," Magana said. "We're not shy about moving people around."

He advised people to stay away from the airport until all danger had passed.

[Update 3:33 p.m. ET] CNN's Ed Lavandera, who was in Dallas when the tornado struck, said there were several isolated cells of storms throughout the area.
Lavandara said the track of one tornado would have taken it through a heavily populated area near the stadiums of the Dallas Cowboys and Texas Rangers, as well as Six Flags amusement park. If the storm had stayed on the ground there, it would have caused catastrophic devastation, he said.

"We right now are in shelter ourselves," Red Cross spokesperson Anita Foster told CNN. "Some of our teams that are on the southern end of the metroplex have started making plans for how we are going to respond . ... Many people are going to need help."

She said Red Cross workers would fan out across the area "as soon as it's safe, as soon as we can get out of our door."
Foster warned people to heed warning sirens and seek shelter in interior areas of structures.
Dallas-Fort Worth International Airport halted all takeoffs and landings until the storm system ends.
CNN meteoroligist said hailstones 3 inches in diameter were being reported. CNN affiliate CBSDFW showed evening-like darkness amid heavy rain at 2:25 p.m. CT.

[Update 3:13 p.m. ET] At 2:05 pm CT (3:05 ET) Tuesday afternoon, trained weather spotters reported a tornado on the ground five miles east of downtown Dallas, Texas. The tornado is moving northeast at 20 mph.

[Update 3:09 p.m. ET] After the tornado passed through, CNN affiliate CBSDFW showed dozens of orange Schneider trucks in various states of damage and disarray.

[Update 2:59 p.m. ET] Separate tornadoes in Texas barreled toward the Dallas-Forth Worth area Tuesday, prompting the National Weather Service to issue tornado emergencies.
Video from CNN affiliate WFAA broadcast dramatic footage of the scene, showing truck trailers being lifted and tossed like toys. Ominous clouds filled the skies.
There were no immediate reports of major injuries or damage, but CNN's Chad Myers said the worst may be yet to come.
"Both storms right now are getting bigger. They both have been rotating, and they both have significant possibilities of damage on the ground heading into DFW," he said.
The weather service urged people in the area to move to a bathroom, closet or hallway on the lowest floor of their buildings and take cover.

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